TNF and hydrops fetalis: Additionally, the increased circulating sphingomyelinase activity and inflammatory factors (tumour necrosis factor α [TNFα] and soluble tumour necrosis factor receptor 1 [sTNF‐R1]) in HF patients can suppress sarcoplasmic reticulum Ca2+ release and blunt myofibrillar Ca2+ sensitivity, which can substantially reduce muscle strength and lean tissue mass.75, 76